16F872 and LCD

[Pic_User]

Hi Fredrick,

Double check that your LCD ground is connected to the PIC Vss (5V common) securely.
Check that your LCD Plus is connected to the PIC Vdd (5V plus).
Also check resistor pullup on PIC MCLR to Vdd. as Skimask suggested.

-Adam-

[Fredrick]

Hi Fredrick,

Double check that your LCD ground is connected to the PIC Vss (5V common) securely.
Check that your LCD Plus is connected to the PIC Vdd (5V plus).
Also check resistor pullup on PIC MCLR to Vdd. as Skimask suggested.

-Adam-

MCLR pull up is ok.

The LCD is connected to the same voltage regulator as the PIC but not directly connected to the VDD or VSS PIC pin.

The LCD is connected to this DEV board.
http://www.olimex.com/dev/pic-p28.html

[Pic_User]

The LCD is connected to the same voltage regulator as the PIC but not directly connected to the VDD or VSS PIC pin.

Same supply as PIC is good.

Does the LCD have a LED back light? The development board voltage regulator (VR) has no heat sink.

[Fredrick]

The LCD does not have a backlight becouse it´s an (HD44780) OLED
For 2 years or so i use the same OLED whit an 16F84 and the same code to and then i worked

No it has not an heat sink, but it is capable of 1.5 A whitout an heat sink and that is more then i need.

http://www.fractronics.com/oled1_b.jpg

[Pic_User]

Hi Fredrick,

The LM317 package would be rated at 1.5A with a very good heat-sink and the correct input voltage, to avoid, dropping too much voltage and heating itself.
(input – output differential V)
http://cache.national.com/ds/LM/LM117.pdf

With no heat sink, 15 V input 5 V output, the 317 could overheat with just over 200 mA at 25 C.

Regulator Heatsink Calculator
http://www.ef-uk.net/data/heatsinking.htm

How much current does the OLED LCD display draw?

Is the voltage regulator getting hot (to your touch)?
Can you “oscilloscope” the +5V supply? Watch for the voltage to dropout.

-Adam-

[skimask]

The LCD does not have a backlight becouse it´s an (HD44780) OLED
For 2 years or so i use the same OLED whit an 16F84 and the same code to and then i worked

No it has not an heat sink, but it is capable of 1.5 A whitout an heat sink and that is more then i need.

Know what else might help?

If you bought a legit copy of PicBasicPro from a vendor instead of download an old version of 2.45 from who knows where!

[Fredrick]

Hi Fredrick,

The LM317 package would be rated at 1.5A with a very good heat-sink and the correct input voltage, to avoid, dropping too much voltage and heating itself.
(input – output differential V)
http://cache.national.com/ds/LM/LM117.pdf

With no heat sink, 15 V input 5 V output, the 317 could overheat with just over 200 mA at 25 C.

Regulator Heatsink Calculator
http://www.ef-uk.net/data/heatsinking.htm

How much current does the OLED LCD display draw?

Is the voltage regulator getting hot (to your touch)?
Can you “oscilloscope” the +5V supply? Watch for the voltage to dropout.

-Adam-

Ok thanx

The VR is not getting hot.

Edit: Heat sink is added just in case...
http://www.elfa.se/elfa-bin/dyndok.p...dok=245171.htm

[Fredrick]

Know what else might help?

If you bought a legit copy of PicBasicPro from a vendor instead of download an old version of 2.45 from who knows where!

That diden´t solve my problem, i still have o use the resistor in serie with Enable.

[Acetronics2]

That diden´t solve my problem, i still have o use the resistor in serie with Enable.

Hi, Fredrick

Why not send us you REAL scheme ??? ... and may be a link to your Oled Datasheet ( couldn't find anything about it yet ...)

looking at various OLED displays Datasheet it seems :


DEFINE LCD_COMMANDUS 4500
DEFINE LCD_DATAUS 150

are the values to use ... not so fast, those OLEDs !!!

Alain